> Many sample apps include internal buffering for single-packet-at-a-time
> operation. Since this is such a common paradigm, this functionality is
> better suited to being implemented in the ethdev API.
>
> The new APIs in the ethdev library are:
> * rte_eth_tx_buffer_init - initialize buffer
> * rte_eth_tx_buffer - buffer up a single packet for future transmission
> * rte_eth_tx_buffer_flush - flush any unsent buffered packets
> * rte_eth_tx_buffer_set_err_callback - set up a callback to be called in
> case transmitting a buffered burst fails. By default, we just free the
> unsent packets.
>
> As well as these, an additional reference callbacks are provided, which
> frees the packets:
>
> * rte_eth_tx_buffer_drop_callback - silently drop packets (default
> behavior)
> * rte_eth_tx_buffer_count_callback - drop and update user-provided counter
> to track the number of dropped packets
>
> Due to the feedback from mailing list, that buffer management facilities
> in the user application are more preferable than API simplicity, we decided
> to move internal buffer table, as well as callback functions and user data,
> from rte_eth_dev/rte_eth_dev_data to the application space.
> It prevents ABI breakage and gives some more flexibility in the buffer's
> management such as allocation, dynamical size change, reuse buffers on many
> ports or after fail, and so on.
>
>
> The following steps illustrate how tx buffers can be used in application:
>
> 1) Initialization
>
> a) Allocate memory for a buffer
>
> struct rte_eth_dev_tx_buffer *buffer = rte_zmalloc_socket("tx_buffer",
> RTE_ETH_TX_BUFFER_SIZE(MAX_PKT_BURST), 0, socket_id);
>
> RTE_ETH_TX_BUFFER_SIZE(size) macro computes memory required to store
> "size" packets in buffer.
>
> b) Initialize allocated memory and set up default values. Threshold level
> must be lower than or equal to the MAX_PKT_BURST from 1a)
>
> rte_eth_tx_buffer_init(buffer, threshold);
>
>
> c) Set error callback (optional)
>
> rte_eth_tx_buffer_set_err_callback(buffer, callback_fn, userdata);
>
>
> 2) Store packet "pkt" in buffer and send them all to the queue_id on
> port_id when number of packets reaches threshold level set up in 1b)
>
> rte_eth_tx_buffer(port_id, queue_id, buffer, pkt);
>
>
> 3) Send all stored packets to the queue_id on port_id
>
> rte_eth_tx_buffer_flush(port_id, queue_id, buffer);
>
>
> 4) Flush buffer and free memory
>
> rte_eth_tx_buffer_flush(port_id, queue_id, buffer);
> ...
> rte_free(buffer);
>
> v3 changes:
> - error counter removed from tx buffer structure, now default behavior is
> silent drop of unsent packets
> - some names was changed in tx buffer structure to be more descriptive
> - two default calbacks are provided: rte_eth_tx_buffer_drop_callback and
> rte_eth_tx_buffer_count_callback
>
> v2 changes:
> - reworked to use new buffer model
> - buffer data and callbacks are removed from rte_eth_dev/rte_eth_dev_data,
> so this patch doesn't brake an ABI anymore
> - introduced RTE_ETH_TX_BUFFER macro and rte_eth_tx_buffer_init
> - buffers are not attached to the port-queue
> - buffers can be allocated dynamically during application work
> - size of buffer can be changed without port restart
>
> Tomasz Kulasek (2):
> ethdev: add buffered tx api
> examples: rework to use buffered tx
>
> examples/l2fwd-jobstats/main.c | 104 ++++------
> examples/l2fwd-keepalive/main.c | 100 ++++------
> examples/l2fwd/main.c | 104 ++++------
> examples/l3fwd-acl/main.c | 92 ++++-----
> examples/l3fwd-power/main.c | 89 ++++-----
> examples/link_status_interrupt/main.c | 107 ++++------
> .../client_server_mp/mp_client/client.c | 101 ++++++----
> examples/multi_process/l2fwd_fork/main.c | 97 ++++-----
> examples/packet_ordering/main.c | 122 ++++++++----
> examples/qos_meter/main.c | 61 ++----
> lib/librte_ether/rte_ethdev.c | 46 +++++
> lib/librte_ether/rte_ethdev.h | 205
> +++++++++++++++++++-
> lib/librte_ether/rte_ether_version.map | 10 +
> 13 files changed, 696 insertions(+), 542 deletions(-)
>
> --
Acked-by: Konstantin Ananyev <konstantin.ananyev at intel.com>
> 1.7.9.5
